Many semiconductor chips are manufactured with solder bumps, balls or lands to enable interconnection to the "outside world". During the production of such chips, it is necessary to contact the solder interconnect areas to allow the chips to be electrically tested. Such tests are often performed during "burn-in" when the chip is subjected to an elevated ambient temperature while being simultaneously electronically operated.
However, it is often the case that the solder interconnect areas do not extend a uniform height from the surface of the chip. Thus, prior art interconnect systems have used connectors which exhibit some flexibility so that the height differences of the solder interconnect areas can be accommodated.
One such connector employs spring loaded pins which automatically adjust to the various solder heights when pressure is applied between the connector and the chip. Spring-loaded connectors are both expensive and present problems when operated in a high temperature ambient. Another type of connector is known as a "probe-card" and includes a plurality of cantilevered, flexible beams which independently make contact with the various solder interconnect areas as the probe-card is brought down upon the chip. Because of the size of the probe-card, the number of chips which can be contacted is limited and registration between multiple chips and the probe card is difficult to achieve.
The prior art also illustrates other types of flexible interconnectors. For instance, in German patent No. GE3151933-A1, a plurality of parallel rows of contacts are embedded in an elastic dielectric matrix. Each contact is designed as a springy wire, thereby enabling the connector to be placed between devices to be electrically interconnected. Then, by pressing the assembly together, the elastic dielectric matrix and springy contacts are compressed and make electrical interconnections. In U.S. Pat. No. 3,680,037 to Nellis et al., a similar interconnection scheme is taught wherein compressible conductive rods are employed to provide electrical contact between a pair of conductive matrices. Here again, the compression of the interconnecting rod assembly between the conductive matrices enables connections to be accomplished. In U.S. Pat. No. 3,862,790 to Davies et al., another interconnection scheme is shown wherein a plurality of parallel conductors are held in a block of insulating material. When circuit boards to be interconnected, via the parallel conductors, they are placed on either side of the interconnection matrix and pressed together-and, the insulating material yields slightly to enable the conductors to make the desired connections.
In view of the very high density of solder interconnect areas on modern chips, the use of flexible connectors may result in inadvertent shorts. Furthermore, flexible interconnect systems, during use, become distorted so that registration with solder interconnection areas is not assured.
Accordingly, it is an object of this invention to provide an electrical interconnector wherein rigid and easily registered contacts are employed.
It is another object of this invention to provide an electrical interconnector for chips which employ solder connection areas wherein height differences in the interconnection areas are accommodated by the contact system.
It is yet another object of this invention to provide an interconnect system for a chip having solder land areas wherein the system is self-aligning.